Hoist



Dec. 17, 19H57 A. E. nu :Bcls

HoIsT .Filed May s. 1955 1N VEN TOR BY' am 2 L. *www HOIST Arthur E. Du Bois, Fortl Lauderdale, Fla., assigner to Aluminum Products, Inc., Fort Lauderdale, Ela., a corporation of Florida Application May 3 1.955., Serial. .50.516,82

s Claims. (Cil. 25,4?167.)I

This invention relates. to hoists or mechanical. Winches, and more particularly it is directed to a hoist for controlling winding and unwnflins Cable and. the like under load pressure.

This invention is an. improvement in the devise. of. my copending application being Serial Number 401,573, filed December 31, 19,513,` now Patent N o. 2,738,954.

An object of this invention is toy provide a hoist having loading and holding pawls, with spring loaded cam mechanisrn c oating therewith in conjunction with reversibly biasing tension means on the loading pawl to controllably wind and unwind cable under lload pressure.

Another object of this invention is to. provide a spring controlled cam for actuating the holding pawl of a hoist of the class described in and out of engagement with a ratchet wheel in multiple step operation.

The foregoing and other objects and advantages of this invention will be more fully understood from reading the following specifications, in conjunction with the drawings, forming a part thereof wherein:

Fig. l is a longitudinal cross-sectional View of the device of this invention; parts shown in elevation for clarity;

Fig. 2 is a plan View of the hoist frame with the legs of the operating bracket shown in partial section; and

Fig. 3 is a perspective view of the holding pawl and cam assembly.

Referring to the drawings, wherein like members are given the same reference numeral, a substantially rectangular frame 1 has an anchoring hook or eye 2, swivelly mounted in one end along the longitudinal axis thereof. The other end of this frame is provided with a boss 3, spaced inwardly from the end member of the frame 1, and aligned apertures 4 and 5 in said boss 3 and of the frame 1, respectively along the longitudinal axis of the frame and adapted to receive and guide a cable 6.

The frame 1, supports a shaft 10, positioned transversely therethrough and press-fitted into bushed apertures 11, provided in the sides of said frame 1. Rotatably mounted on the shaft is a ratchet wheel drum comprising a cylindrical body 12, an annular flange 14 on one end and a ratchet wheel 15 on the other end. A U-'shaped operating member or bracket 16, having approximately the same transverse dimension as the frame 1, has the legs thereof rotatably mounted on the shaft 10, one leg 16 intermediate the ange 14 and side of the frame 1, and the other leg 16" externally of the frame 1, on the side adjacent the ratchet wheel 15. To this latter leg 16 of the U-shaped member 16, is an operating lever or arm, not shown, fastened thereto in a conventional manner, receiving the shaft 10, and a transverse feed pawl shaft 20 is rotatably supported by the U-shaped member 16. A loading or feeding pawl 21, is rotatably mounted on the shaft 20, in alignment with the ratchet wheel 15. A guide 13, fastened to said shaft 20, has an apertured ear 25, adapted to receive one end of an L- shaped toggle spring element 26, having the other end thereof pivotally mounted in an aperture 27 of the central section of the U-shaped member 16. The feeding States Patent r'ice lpawl 2,1, is provided with a pair of ears 28 and ,29, be.- tvveen which the spring element 26 passes. When the shaft 20 is in the position illustrated in Fig. 1, the spring @lement 26 is past its center point and presses against ear 28, to urge the feed pawl 21 into engagement with ther ratchet wheel 15; whereas, with the shaft 20 rotated back approximately a fourth revolution by turning knob 31, the spring 26 is biased in the opposite direction and pressed a.gainst ear 29, raising the feed pawl 21 from engagement with the ratchet wheel 15, and to over-ride the wheel 15 as illustrated in my aforementioned patent.

A shaft 40 is journaled in the side members of the frame 1, and pivotally supports a holding pawl 4l thereon, whereby the, holding pawl is aligned with the ratchet wheel 15 for `engagement therewith and pivoted out of engagement therewith. Pivotally mounted to the frame 1 intermediate the frame 1, and holding pawl 41, is` a cam element 42,. having a projection 413, J'Qurnaled for free rotation in an aperture 44 in the frame 1. The cam element 42 has a hook 45, provided on the` free, end thereof adapted to engage in one direction a stud projection 46 on the holding pawl 41. A compression spring 47, illustrated as a U-shaped spring, has one end thereof fastened to the cam 42., and the other end thereof fastened to the stud projection 4,6 of the holding pawl, urging the holding pawl 41 out of engagement with the ratchet wheel 1S; but, another spring element 48 of greater strength than spring 47, illustrated as a tension spring 48, has one end thereof fastened to the carn element 42, and the other `end fastened to one leg of a U-shaped spring 50, having the other leg fastened to the frame 1 in any conventional manner such as pressing one end in a frame aperture to oppose the force of spring element 47, and urge the holding pawl 41, into engagement with the ratchet wheel 15, by the hook 45 abutting the stud 46 and pulling the pawl 41 towards the ratchet wheel 15, over the opposed force of the compression spring 47. The holding pawl 41 has a projection 49, extending beyond the frame 1, to permit manual disengagement of the holding pawl 41 from the ratchet wheel 15, by rotating the pawl over the action of the spring 48.

The loading pawl 21 extends transversely beyond the ratchet 15 to abut the cam 42, when the loading pawl 21 is in over-ride position as illustrated in my aforementioned patent to rotate the cam 42 and compress spring 47, while overcoming the action of the spring 48. After the loading pawl 21 is cammed into ratchet engagement, the spring 47 disengages the holding pawl 41 from the ratchet wheel 15. When the direction of movement of the loading pawl 21 is reversed, there is a slight delay until the hook 45, contacts the projection 46, forcing the holding pawl 41 into engagement with ratchet 15 one tooth less than prior engagement to lower the load one tooth at a time by repeated cycle.

In operation, with a cable 6 served to the drum 12, and the loading pawl 21 in over-ride position, by pulling the holding pawl projection 49 towards the drum 12, to release the holding pawl 41 from the ratchet wheel 15, the cable 6 may be freely moved to a load. When the knob 31 is turned to load position by rotating the bracket 16, counter-clockwise, the loading pawl 21 engages the ratchet wheel 15 to wind the cable 6 onto the drum 12, with the holding pawl 41 operating normally to prevent back rotation of the drum of engaging the ratchet wheel 15.

When it is desired to lower a load which has been raised, the loading pawl 21 is placed in over-ride position. Rotation of the bracket 16 permits the loading pawl 21 to over-ride the ratchet wheel 15 until it contacts and rotates the cam 42, overcoming the force of spring 48 and 5t) and compressing spring 47, after which while camming loading pawl 21 into ratchet 15 engagement, holding pawl 41 is forced from engagement with the ratchet wheel 15 by spring 47. When the bracket 16 is reversed the hook 45 contacts the projection 46 on the holding pawl 41, forcing it into engagement with ratchet wheel 15, in the next preceding tooth, thus lowering the yload one ratchet tooth distance. Repeated action lowers the load a tooth at a time.

The tension spring 48, being fastened to the free end of the U-shaped spring 50, permits free movement of this spring under tension, avoiding separation of the spring and assuring more positive action.

This invention has been described in detail, but it is clearly understood that it is not so limited. Many changes and modifications can be made therein without departing from the spirit and scope thereof, as defined in the appended claims.

Having thus described the invention, what is claimed is:

1. A hoist comprising a frame, a drum having a ratchet wheel rotatable therewith, an operating member, a loading pawl rotatably mounted on said operating member and substantially in alignment with said ratchet wheel, a spring biasing said loading pawl, means changing the direction of bias of said spring, a holding pawl pivotally connected to said frame and in alignment with said ratchet wheel, a cam pivotally mounted intermediate said pawls and positioned intermediate said frame and said holding pawl, resilient means connecting said cam and holding pawl and biasing said holding pawl out of ratchet engagement, spring means connecting said cam and frame and biasing said cam opposed to the said resilient means connecting the cam and holding pawl, and co-operating members on said cam and holding pawl to urge said holding pawl into ratchet engagement.

2. A hoist comprising a frame, a drum having a ratchet wheel rotatable therewith, an operating member, a loading pawl rotatably mounted on said operating member and substantially aligned with said ratchet wheel, means yselectively biasing said pawl in and out of ratchet engagement, a holding pawl pivotally connected to said frame and in alignment with said ratchet wheel, a cam pivotally connected to said frame intermediate said pawls and intermediate said frame and holding pawl, spring means biasing said cam towards said loading pawl, means on said cam contacting means on said holding pawl to urge said holding pawl towards said loading pawl and into ratchet engagement, and compression spring means connecting said cam and holding pawl biasing said holding pawl out of ratchet engagement.

3. The device described in claim 2 in which said spring means biasing said cam towards said loading pawl comprises a tension spring fastened to said cam, and a second spring fastened to the frame at one end and to said tension spring at the other end.

4. The device of claim 2 in which said loading pawl is of suflicient length to contact said cam and rotate it to compress said cam and loading pawl spring while being cammed into ratchet engagement.

5. The device of claim 3 in which said second spring is a compression spring.

References Cited in the file of this patent UNITED STATES PATENTS 552,044 Crooker Dec. 24, 1895 

